Cutting crop material such as straw or silage requires a large amount of power from the tractor, and the better the knife quality, the less fuel the tractor consumes. When the knives are not sharp anymore, the pressure, and hence the force on the knife raises, resulting in the knives sliding backwards and disappearing at least partially out of the crop flow into the knife drawer. This is made possible by spring loading each knife. By spring loading the knives, the infeed cutter is protected against solid foreign objects, avoiding that the knives break when foreign objects enter into the infeed cutter.
In prior art systems, if an operator wants to get in an indication of the knife sharpness, he needs to physically examine the knives. Such an examination is time consuming and requires the baler to be stopped.